Here’s an idea for a Coker frame: The Krashin Kenny Kustom Koker
Easier to make than the Hunter style design. You can probably find a suitable magnesium fork crown, add on the titanium tubing and you’ve got yourself a Custom Coker frame. Easy measurements for the tubing and minimal forming and welding.
It’s not an ideal frame design because the crown will be a little wider than necessary. If you’re short, or if you have stocky legs, your thighs may rub on the crown. So it all depends.